When a tire is molded both initially and when retreaded or recapped (hot process), "nibs", like cat's whiskers, are formed on the molded exterior surfaces thereof in correspondence to the locations and shape of small conduits necessarily provided in most tire molds.
Some tires are sold with those nibs still protruding therefrom, but it is believed many among the tire-buying public associate the appearance of untrimmed nibs on a tire with lack of attention to finishing detail, rougher and perhaps less careful work, and, in short, a tire to be less preferred over one of similar price and apparent quality which has been trimmed.
So, many tire manufacturers and retreaders trim the nibs from their products to give them a finished appearance and a better chance in the marketplace.
For similar reasons, and to protect the tires before they are used, tire manufacturers and retreaders usually "paint" their product, with a black paint over black areas of the tire and a clear or sometimes bluish protective coating over the white wall side of the tire.
Apparatus in the prior art for trimming nibs has ranged from simple hand-held knives run over the tire's exterior, to complicated machinery. Likewise, painting apparatus has ranged from a brush and a bucket to automated spray booths.
On the manual end of the scale, the equipment is less expensive, but the output can be highly variable in quality and in quantity-per-time. The tasks involved are ones which it is becoming increasingly more difficult to find willing workers to do well.
On the automated end of the scale, the equipment available up until now has been too bulky and expensive and too much a mystery to maintain for most smaller manufacturers and independent retreaders.
More specifically, the prior art now known to the present inventor includes the following United States patents.
The patent to Groves et al, 3,075,574, issued Jan. 29, 1963, relates to an automatic tire trimming assembly. Tires are fed into the trimming area by a conveyor. When the tire drops into the trimming area, a limit switch 213 actuates a cam switch motor 214. The trimming cams then control all of the machine's operation by energizing the tire trimmers, the relating assembly and tire ejecting mechanism. The equipment is totally automatic after the operator puts the power switch on. No paint cycle is mentioned.
The Strong patent, 1,983,684, issued on Dec. 11, 1934, illustrates performing tire trimming and painting operations in one apparatus.
The patent to Bosomworth et al., 2,996,110 issued Aug. 15, 1961, discloses an automatic tire trimming apparatus. Tire 9 rolls down conveyor 3 and trips a switch that actuates a motor 19 to initiate the machine cycle.
The patent to Broden, 2,581,928 issued Jan. 8, 1952, although it relates to a wheel finishing machine, discloses a conveying system including an automatic in and out fed feature.
The patent to Lindemann, 2,603,290 issued July 15, 1952, discloses the use of oscillating knives for tire trimming apparatus.
The patent to Strong 2,524,489 issued Oct. 3, 1950, illustrates an apparatus for trimming protuberances from tires. When the tire comes in contact with a limit switch 110, a timer motor is begins. The cutting blades are oscillated as the cutting operation beings. After the tire makes one revolution, the cutting blades are retracted from the tire surface, and the lift roller 37 releases the tire to be removed from the machine.
The following patents disclose various other manual and automatic tire trimmers and groovers:
McLaughlin et al 2,034,662 March 17, 1936 Dinnan 2,606,612 August 12, 1952 Wikle et al 2,815,073 December 3, 1957 Skinner 2,863,506 December 9, 1958 Hawkinson 2,945,534 July 19, 1960 Ebers 3,260,297 July 12, 1966 Warnecke et al 3,262,483 July 26, 1966
In this specification, no distinction is made between the terms "retread" and "recap"; for the purposes hereof, one is synonymous with the other.